# NTSB CEN17LA286: Beech V35, N6257V, Walters, OK, July 8, 2017 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 8, 2017, 10:50 local (15:50 UTC) - Place: Walters, OK - Coordinates: 34.399166, -98.266387 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=34.3992&lon=-98.2664&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 2 minor - Status: Completed, report April 13, 2020 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA FSDO, Continental Engines - NTSB case key (mKey): 95674 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN17LA286 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/95674/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=95674 - Page: https://openairdocs.org/ntsb/CEN17LA286 ## Probable cause Maintenance personnel’s installation of an improper vacuum pump gasket, which resulted in oil starvation to the engine and a subsequent total loss of engine power. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Misc hardware](https://openairdocs.org/ntsb-findings/01071400): Aircraft › Fluids/misc hardware · Incorrect service/maintenance (probable cause); cases with it: [Beech V35, 1 case](https://openairdocs.org/ntsb-findings/01071400/cases.md?model=1151538), [All aircraft, 41 cases](https://openairdocs.org/ntsb-findings/01071400/cases.md) - [Maintenance: installation](https://openairdocs.org/ntsb-findings/02062035): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Beech V35, 2 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md?model=1151538), [All aircraft, 371 cases](https://openairdocs.org/ntsb-findings/02062035/cases.md) - [Fluids: oil](https://openairdocs.org/ntsb-findings/01071020): Aircraft › Fluids/misc hardware · Fluid level (probable cause); cases with it: [Beech V35, 4 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md?model=1151538), [All aircraft, 174 cases](https://openairdocs.org/ntsb-findings/01071020/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Beech V35, 10 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=1151538), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Landing: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Beech V35, 9 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=1151538), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The airline transport pilot was conducting a personal, cross-country flight. He reported that, about 10 minutes after takeoff, the oil pressure decreased to 0, and the engine experienced a loss of all power. The pilot conducted a forced landing on a soft field about 1 mile short of an airport, during which the airplane sustained substantial damage to the firewall and lower fuselage. A review of the airplane's maintenance records revealed that the vacuum pump had been replaced the day before the accident. Examination of the engine revealed that three connecting rods exhibited thermal and impact damage, and three rod journals were found dry and exhibited thermal discoloration, indicative of oil starvation. Disassembly indicated that a gasket typically used for carburetors was installed on the vacuum pump. The installed gasket did not completely cover the high-pressure oil orifice on the vacuum pump mounting fixture, which resulted in oil leakage, subsequent oil starvation to the engine, and the loss of engine power. ## Factual narrative On July 8, 2017, about 1050 central daylight time, a Beech VA airplane, NV, sustained substantial damage during a forced landing after a loss of engine power near Walters, Oklahoma. The airline transport pilot and one passenger sustained minor injuries. Visual meteorological conditions prevailed and no flight plan was filed. The airplane was registered to Gas Corporation of America of Wichita Falls, Texas, and the flight was being operated by the pilot under the provisions of Title 14 Code of Federal Regulations Part 91. The flight originated at 1040 from Kickapoo Downtown Airport (CWC), Wichita, Falls, Texas, and was en route to Lawton, Oklahoma. The pilot reported that about 10 minutes after departing CWC, the oil pressure went to zero and the engine failed. He executed a forced landing to a soft farm field, about one mile south of the Walters Airport (OK12). The pilot and passenger exited the airplane with minor injuries. The airplane sustained substantial damage to the firewall and lower fuselage. A review of the airplane maintenance records showed that the vacuum pump was replaced on July 7, 2017, the day before the accident. The engine was visually examined and disassembled. During the disassembly, it was discovered that a improper gasket (P/N-21051) was installed on the vacuum pump. The gasket was normally used for the installation of a carburetor. The installed gasket did not completely cover the high-pressure oil orifice on the vacuum pump mounting fixture. The proper gasket was (PN-MS9134-01) for the vacuum pump. Three connecting rods showed thermal and impact damage, and three rod journals were observed to be dry and showed thermal discoloration. ## Aircraft - Registration: [N6257V](https://openairdocs.org/deregistered/N6257V-2019-10-05), registration cancelled 2019-10-05, S/N D-8587, built 1967 (OpenAirDocs) - Reported make and model: BEECH V35 (UNDESIGNAT) - Registry model: [Beech V35](https://openairdocs.org/model/beech-v35) (registry code 1151538) (OpenAirDocs) - Registry engine: [Continental IO-520 series](https://openairdocs.org/engine/continental-io-520-series) (registry code 17032, reciprocating) (OpenAirDocs) - Category: Airplane - Serial number: D-8587 - Year built: 1967 - Airframe hours: 3432 - Engines: Continental IO-520-BB6 300 horsepower reciprocating - Damage: Substantial damage - Flight: Personal, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, February 7, 2017, 10 hours before - Departed: CWC, Wichita Falls, TX - Destination: LAW, Lawton, OK - Airport: OK12, Jones Farm Field Airport - Equipment: Stall warning system ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 48; injuries: none; airline transport; airplane ratings: multi-engine land, single-engine sea; instrument ratings: airplane; medical: class 1, without waivers/limitations; seat: left; restraint: lap only; flight hours: 5,000 total, 26 in this make and model, 20 in the last 90 days, 1 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 130° at 3 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 77 °F, dew point 72 °F - Altimeter: 30.06 inHg - Observed at: LAW, 20 nm away ## FAA reports on this event (1) The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs). - [Accident 20170708009809A](https://openairdocs.org/incident/20170708009809A), Jul 8, 2017: Beech V35, Walters, OK, Substantial damage. Saturday morning July 8, 2017. [privacy data omitted] [privacy data omitted] departed wichita falls, Texas at about 1030 am. [privacy data omitted] Was the… ## Other investigations on N6257V (1) From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. - [NTSB MIA68D0323](https://openairdocs.org/ntsb/MIA68D0323), Dec 23, 1967: Beech V35 (N6257V), Pompano Beach, FL, substantial damage ## Docket (7 files) The files NTSB released with the investigation on January 3, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=95674. 2.5 MB in all. - Memorandum for the Record Pilot Statement CEN17LA286 (item 1, .PDF, 180 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479614&FileExtension=.PDF&FileName=Memorandum%20for%20the%20Record%20Pilot%20Statement%20CEN17LA286-Master.PDF - Passenger Statement CEN17LA286 (item 2, .PDF, 432 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479615&FileExtension=.PDF&FileName=Passenger%20Statement%20CEN17LA286-Master.PDF - Recent Maintenance Record to Replace Engine Cylinders (item 3, .PDF, 346 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479616&FileExtension=.PDF&FileName=Recent%20Maintenance%20Record%20to%20Replace%20Engine%20Cylinders-Master.PDF - Memorandum for the Record Engine Examination Summary of Findings CEN17LA286- (item 4, .PDF, 210 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479617&FileExtension=.PDF&FileName=Memorandum%20for%20the%20Record%20Engine%20Examination%20Summary%20of%20Findings%20CEN17LA286--Master.PDF - Recent Maintenance Record to Replace Vacuum Pump CEN17LA286x (item 5, .PDF, 242 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479618&FileExtension=.PDF&FileName=Recent%20Maintenance%20Record%20to%20Replace%20Vacuum%20Pump%20CEN17LA286x-Master.PDF - Memorandum for the Record Vacuum Pump Gasket Examination CEN17LA286 (item 6, .PDF, 475 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479619&FileExtension=.PDF&FileName=Memorandum%20for%20the%20Record%20Vacuum%20Pump%20Gasket%20Examination%20CEN17LA286-Master.PDF - Photo Array CEN17LA286 (item 7, .PDF, 596 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40479620&FileExtension=.PDF&FileName=Photo%20Array%20CEN17LA286-Master.PDF From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.